Reactions of 6-aminouracil with an excess of oxiranes (ethylene oxide and propylene oxide) in dimethylsulfoxide in the presence of triethylamine as a catalyst leads to polyetherols with a 1,3-pyrimidine ring. The products are analyzed using IR and (1)-HNMR spectroscopies. The physical properties and thermal stability of the prepared polyetherols are investigated. (c) 2006 Wiley Periodicals, Inc.